Rotary pump



April 7, 1931. A. v; JENSEN ROTARY PUMP Filed Oct. 21, 1929 3 Sheets-Sheet 1 INVENTOR .Amos Tfifenserz,

ATTONEY W A. v. JENSEN 1,799,237

' ROTARY PUMP Filed Oct. 21, 1929 3 Sheets-Sheet 2 INVENTOR Amos V. Jensen,

A ril 7, 1931.

A. v. JEN SEN 1,799,237

ROTARY PUMP Filed Oct. 21, 1929 5 Shets-Sheet '5 INVENTOR Amos V. Jensan,

ZBY. '.%ATTORNEY of the device, and prevent possibility of. toot Patented 7, 1931 UNITED STATES PATENT OFFICE Amos vnrmnn JENSEN, or CEDAR rALLs, Iowa, ASSIGNOR T0. VIKING PUMP corrrANY, or CEDAR rms- Iowa norm: rm

' Application filed October 21, 1929. Serial No. 401,191.-

My'invention relates to im rovements in rotary pumps and motors, an i the object of my improvement is to provide release means for entrapped liquids in such devices to reduce wear of the rotating parts, reduce power consumption, increase mechanical eflicienc fracture caused b excessive hydraulic pressures from liqui imprisonment at certain places within such devices.

This object I have successfully achieved bythe means which are hereinafter described and claimed, and which are illustrated in the I accompanying drawings, in which Fig. 1- is a front elevation of a rotary uinp with the cylinder cover removed, an .with a part broken away. Fig. 2 is an axial vertical longitudinal sectionl of the complete pump, with parts broken away. Fig. 3 is an eleva-' tion of the inner face of the cylinder cover showing its liquid relief passage, and Fi 5 is a similar elevation. showing a modi ed kind of said passage.,lFig. 4t is-a transverse section of the pump, with parts broken away,

taken-on the broken line 4-4 of said Fig- 2 and looking in the direction indicated'by-the.

. arrow. Figs. 6 and 7 are like elevations of a rotary pump in each case'having a modified arrangement of intermeshing gears 0r pistons therein, Fig. 7 showing a pair of relief passages for delivery in one direction only the Flg. 6 showing these passages arranged and shaped to permit the actionof the pump to be reversible.

These drawings illustrate wellknown types of rotary pumps. My liquid relief" means in each case is shown incorporated such means, modified asmay be necessary, may be of any kind and used with any other s ecies of rotary pumps or motors without eparting'from my invention, or from theprotection of the appended claims.

discoidal cylinder-header cover 17 secured thereon by machine screws 18' remo'vably.

The rear part of the cylinder 1-has an integral and axially apertureddiminished the sleeve extension 2 within-which is fitteda bushing 9, and the latter together'with said extension 2 have-- communicating apertures 10 to an'oil-cup 11 to lubricate 9. contained shaft 5.

art of the hollow of the extension secures a rotor 6 on the shaft 5 within the hollow? of the cylinder 1 to fit it circumferentially, the rotor having on-its front face inwardly directed crown teeth 7'.

The cylinder-head 17 has an outwardly and forwardly directed centrally apertured eccentric boss to receive a headed screw 19. The aperture of said boss and head is coned forwardly and a pintle .20 has a threaded part to seat thereon the nut 19 and to secure the same thereon, the inner face of the head 17 having an annular groove 22 concentric around the pintle to partially receive a bear' ing bushing 21, a spur-toothed idler23 being fixedly mounted on the bushing 21, the'bushing giving more bearing on the surface of W011 d'normally allow. The idler is positioned within the hollow between the crown teeth' of the rotor 6, providing an internal gear, the teeth of'the idler successively inter-' meshing with said crownteeth 7 at the top,

to be interposed between the spaced teeth f of the idler and rotor at the bottom below the pintle 20, thus closing their interspace with the pump, but. it is to be understood that th ere.

The numerals 16 and 15 denote laterally opgosite chambers provided in the cylinder, an

having terminal ports foricommunicatlo'n with pipes not shown to deliver. a liquid into thecylinder, and todischarge it therefrom respectively, these chambers also com-q muincatin with the cylinder cavity -3 at' opfiosite sides thereof.

eferrin'g tosaid Fig. 3, the numeral 27 denotesaliquid relief passage formed in the inner. face of 'thecylinder-head 17. The

upper end of this passage has a communica pintle than the actual width of the idler tion with a longitudinal recess 14 in the upper part of the cylinder.

The passage part 27 extends downwardly circularly at 28 around the idler bushing 21 and terminates at its lower end in a horizontally elongated transverse open hollow 29 of sufficient length that it can at no time be completely covered by a passing gear tooth.

Referring to said Figs. 2 and 4, the numeral 14 denotes a longitudinal rectangular downwardly opening groove or recess in the top of the inner circumferential wall 3 of the cylinder 1 where the wall is an abutment separating the chambers 15 and 16, and which is contacted rotatably by the idler teeth 24 when in full mesh with the crown teeth 7 on the rotor 6. The recess 1 is in communication with the wall passage 27 at the top of the latter and receives the liquid which becomes trapped in the space 33 between the tops of the idler teeth 24, the sides of the rotor teeth 7 and'the wall. of the abut ment.

The sides of the rotor teeth 7 are convex while the sides of the idler teeth 24: are concave to properly mesh in their coacting positions. When a rotor tooth 7 at the top of the cylinder is completely in mesh with the idler teeth 24, there is a cavity at the root of the idler teeth in which is trapped or imprisoned a portion of liquid, which, being incompressible, receives from the intruding rotor tooth 7 a pressure which is communicated through the trapped liquid to the idler and to the pintle 20, exercising excessive frictional pressure upon the latter.

In actual practice and under normal conditions a good rotary pump has a volumetric efiiciency of' from approximately 90 to 96 per cent, the balance bein lost due to what is termed slippagez part of thisfslippage is due to the fact that the interdental' spaces receiving liquid from the suction port of the ump do not become 100 per cent filled; his is due to the fact that most r0 tary gear pumps usually musttake liquid.

into the rotating elements against opposing, centrifugal force. The interdental spaces therefore which are receding from the'suction port contain the larger percent of liquid with the balance a vacuum.

Upon exposureto the discharge port the existingliquid pressure therein replaces the small spaces formerlyoccupied by the Vacuum and intermeshing of the gear teeth begins,

whereby the liquid is expelled into the discharge port excepting for the balance of the small percentage termed as slippage that' becomes t 'apped between the teeth of the intermeshi' gears, causing hammering, excessive wea mucli loss of' driving power, no se, vibrati and sometimes actual tooth fracture. The liquid then escapes into the suction opening. This liquid is by my device led from the points where trapping occurs toa neutral area connecting with the tooth spaces that have just rece ed from the suction opening and which as before mentioned are not completely full, thereby permitting the heretofore entrapped liquid to ass thereinto at a much reduced pressure w iich greatly diminishes the objectionable characteristics previously cited.

Comparative tests between rotar pumps supplied with such passages as a ove described, prove that such passages serve to greatly enhance the efliciency of the devices in different ways. These tests show that the pumps supplied with these passages require eleven and three quarters percent less operating power than the unsupplied pumps. Noise, vibration and hammering are immediately greatly reduced and possibility of tooth fracture from the aforesaid reasons made very remote.

Furthermore, in pumps handling very viscous liquids such as tar, glucose, malt syrups and lacquers which naturally resist movement, the spaces between the teeth of the r0- --tating elements receding from the suction opening contain a greater percentage of vacuum than ordinarily due to the movement of the gears not allowing sufficient time for the spaces to become completely filled with such heavy slow moving liquids. Consequently the filling of these vacuum pockets at the discharge opening occurs with a decided impact setting up a very injurious vibration throughout the pump and piping s stem. This naturally rapidly wears out an dislocates the device. However, due to the relief passage the vacuum pockets are almost completely nullified, greatly diminishing harmful action as described. Y

In Figs. 6 and 7' are shown like pumps having like intermeshing piston gears 31 and 32 of a well known type, the pump-cylinder 1 having opposite recelvin and discharge ports 16 and 15 located media 1y. In this type of pump, see Fi 6, the gears mesh in such a manner that t e root closed cavities at 27 are alternately shifted from one ear to the other, so that a pairof like relief passages 27, 28 and 29, like the passage of Figs. 1 to 4;, are

employed to successively'and alternately re ceive liquid imprisoned in said cavities. The only difference between the ass'ages of. said Figs. 6 and 7 is in the fact t at the passages in the device ofF-ig. 6 are adapted to deliver liquid to a neutral area and conveyed to the discharge port, the device being. reversible inter-meshing gear teeth in such devices may be positioned as desired relative to the. diflferent parts thereof which coact therewith, and

such relief means may be used with any rotary pump or motorwithout departing from the invention herein.-

Having described my invention, what I claim as new, and desire to secure by Letters Patent,is: v

1. A rotary pump or motor, comprising a casing having an inlet port'and a discharge port, intermeshing driving and driven pistons in said casing, said pistons being a crown gear and an idler spur gear mounted eccentri cally relative to the crown gear and meshing internally therewith, means for closing the inters'pace between the gears opposite their intermeshing teeth, said casing having aconduit positioned to communicate intermittent- I liquid imprisoned within said spaces, and

0f the outer end of an advancing tooth of said ly successively with the spaces between the in; termeshing teeth to release its contents to a neutral area within the device to be conveyed thence to said discharge port, to thusrelease said conduit having one end part ,extended and positioned for receivin and preventing the trapping of liquid within the interspace idler spur gear and the wall of the casing before the complete meshing of said tooth with teeth of saidcrown gear.

2. A rotary pump or motor, having a casing with oppositely located inlet and discharge ports, and intermeshing rotor and idler pistons between said ports, said casing pistons, and a wa'll cavity in said casing in. communication with said passage for receiv-. ing and preventing the trapplng of having a relief passage to effect communication successively with the spaces between. intermeshed parts of the pistons to recelve and release liquid imprisoned between the uid within the interspace of the outer end o f an advancing part of the idler piston and the.

wall of the casingjbe'fore the complete meshing of said part with a. coacting part of the rotor piston.

In testimozhwhereof I afixm signature.

os-vEnNER NSEN. 

